Strain difference in jejunal crypt cell susceptibility to radiationinduced apoptosis

Abstract

Levels of radiation-induced jejunal crypt cell apoptosis were compared in C57BL 6J, C3Hf Kam and C3H HeJ mice. Apoptosis levels were consistently lower in the C3H strains than in C57BL 6J. Although other explanations are possible, the strain difference is most likely to have a genetic basis, and in fact a preliminary analysis of the F2 progeny of C3H HeJ and C57BL 6J mice indicates that more than one gene is involved. Both C3H strains also had lower levels of radiation-induced thymocyte apoptosis than C57BL 6J mice. Jejunal crypt cell apoptosis levels did not co-segregate with thymocyte apoptosis levels in the F2 progeny of C57BL 6J and C3H HeJ mice. These results imply that the genes responsible for the difference in radiation-induced thymocyte apoptosis levels between these two strains are not the same as those responsible for the strain difference in radiation-induced jejunal crypt cell apoptosis levels. The experiments reported here identify strain-specific differences in levels of radiation-induced crypt cell apoptosis and are a first step towards identifying genetic polymorphisms that influence sensitivity of the small intestine to damage from ionizing radiation.